[Bacterial epidemiology of acute otitis media]

Since the middle of the 1980's, Haemophilus influenzae is the most common bacterial species responsible for acute otitis media in France, followed by Streptococcus pneumoniae. Haemophilus influenzae has maintained its leading position since 1985, but the rate of pneumococcal acute otitis media is increasing fairly steadily. The other recent change with regard to the distribution of bacterial agents is the emergence, four years later than in North America, of Branhamella catarrhalis which currently accounts for 10% of cases of acute otitis media. Modifications in the behavior of microorganisms in relation to antimicrobials usually given to treat upper respiratory tract infections have occurred. Staphylococcus aureus and Branhamella catarrhalis have always exhibited marked resistance to ampicillin due to the production of beta-lactamases. Resistance of Haemophilus influenzae to ampicillin has been increasing gradually since 1985, again with a lag of a few years as compared with the United States; at present, this form of resistance is seen in approximately 35% of strains. More recently in France, 20% of pneumococcal strains recovered from middle ear pus have been shown to have abnormal susceptibility to penicillin. These changes in the behavior of the two main pathogens, i.e., Haemophilus influenzae and Streptococcus pneumoniae, require implementation of rigorous multiregional epidemiologic surveillance programs and may justify reappraisal of current therapeutic approaches.